Phone: 09847255972 Address: Dr. K. B. Padmakumar Assistant Professor Department of Marine Biology, Microbiology & Biochemistry School of Marine Sciences Cochin University of Science & Technology Kochi-16, Kerala, INDIA
504-506Neoceratium platycorne (Daday) F. Gomez, D. Moreira, P. Lopez-Garcia is reported for the f... more 504-506Neoceratium platycorne (Daday) F. Gomez, D. Moreira, P. Lopez-Garcia is reported for the first time from the North Eastern Arabian Sea (NEAS). Species was observed in the open ocean subsurface waters of NEAS during the late winter monsoon period. Cell density of the <i style="mso-bidi-font-style: normal">N. platycorne was 10-15 cells L-1. This record will contribute to the phytoplankton checklist of the Indian EEZ
856-859Marine epizoic diatom, Pseudohimantidium pacificum Hustedt and Krasske 1941, on copepod Co... more 856-859Marine epizoic diatom, Pseudohimantidium pacificum Hustedt and Krasske 1941, on copepod Corycaeus affinis is reported for the first time in North Eastern Arabian Sea. It was found attached exclusively to copepod C. affinis. Light Microscope and Scanning Electron Microscopic studies were made to examine the frustule morphology. With the present report from the North Eastern Arabian Sea, the biogeographic boundary of this species can be extended to the Indian waters
A monospecific bloom of thecate dinoflagellate Gonyaulax polygramma (5x 10 8 cells L -1 ) was obs... more A monospecific bloom of thecate dinoflagellate Gonyaulax polygramma (5x 10 8 cells L -1 ) was observed from the shelf waters off Mangalore (South Eastern Arabian Sea) during late summer monsoon. The bloom was observed to be subsurface (~5m depth) with chlorophyll a maxima of 13.15 μg L -1 . The species observed to be photosynthetic and no visible food vacuoles were observed within the cell. Water column stability with sufficient inorganic nutrients during the fag end of summer monsoon might have favoured the bloom species. The region observed complete exclusion of zooplankton and can suggestively due to unpalatability of the bloom species.
Crab jubilee associated with red tide of Noctiluca was observed along the central Kerala coast du... more Crab jubilee associated with red tide of Noctiluca was observed along the central Kerala coast during the summer monsoon of 2013. There was an unusual shoreward mass movement of blue swimming crab Portunus pelagicus throughout the day. Hypoxia caused by red tide of Noctiluca in the coastal waters as well as sluggish upwelling by fresh water surfacing during the intense rainfall might be the reason for this unusual coastal phenomenon.
Abstract The dynamics of Northeastern Arabian Sea (NEAS) is governed by convective mixing in wint... more Abstract The dynamics of Northeastern Arabian Sea (NEAS) is governed by convective mixing in winter and stratification during the inter-monsoon spring seasons, wherein blooms of green Noctiluca scintillans is a recurrent phenomenon. The study investigated the role of microzooplankton (MZP) in mediating the microbial food web in bloom waters of Noctiluca scintillans. The winter monsoon and inter-monsoon spring periods for the years 2009, 2011 and 2012 were considered for the present study as the occurrence and intensity of bloom fluctuates between these seasons. The MZP mediation seems to be through the top-down controls (preferential grazing) on ciliates (CTS) in bloom waters, consequently supporting high mesozooplankton standing stock and inevitably higher stock of copepods. Among the three years of observations, this relation was noticeable for the year 2012, as the intense bloom of Noctiluca (3 ×107 cells L−1) coincided with the highest number of copepods. On the contrary, in the non-bloom waters, a simple classical food web seems to be operational as diatoms dominated the phytoplankton community. Furthermore, the functional role of two CTS species viz. Codonellospsis ecaudata and Steenosemella ventricosa were most influential in structuring the community and microbial food web in the bloom events. The study suggests that during the bloom of Noctiluca scintillans, MZP mediated food web seems to be relatively significant in sustaining the high secondary production in the NEAS.
Annales de Limnologie - International Journal of Limnology, 2020
Microcystis aeruginosais a potentially toxic bloom-forming freshwater cyanobacterium, usually fou... more Microcystis aeruginosais a potentially toxic bloom-forming freshwater cyanobacterium, usually found in eutrophic water bodies worldwide. The present study reports the occurrence ofMicrocystis aeruginosaand its bloom in freshwater ponds along central Kerala (south India). Monitoring of cyanobacterial blooms was conducted from May 2019 to February 2020 along the aquatic ecosystems of central Kerala and theM. aeruginosablooms were recorded from two freshwater ponds of Kochi. Massive blooms ofM. aeruginosawas observed during the period prior to summer monsoon (May) with an abundance of 1.17 × 106cells L‑1(Station 1) and during early summer (February) latter being more thick scum (2 × 108cells L‑1) with high chlorophylla. Dense aggregates ofM. aeruginosascums were more prevalent during the periods characterised by higher Surface Water Temperature (SWT). The nutrient characteristic pattern of the study area showed the abundance ofM. aeruginosacorrelated very well with higher dissolved nit...
Journal of the Marine Biological Association of the United Kingdom, 2016
Winter cooling and persistent mixing for more than a quarter of year (November to early March) al... more Winter cooling and persistent mixing for more than a quarter of year (November to early March) along the North Eastern Arabian Sea (NEAS) results in nutrient enrichment of the euphotic column thereby triggering biological production. Hydrographic characteristics of NEAS during Late Winter Monsoon (LWM) and Early Spring Inter Monsoon (ESIM) and the influence on biological production are overviewed here. Winter convective mixing signatures were evident during LWM with low SST (24°C), high SSS (36.4), deep mixed layers (>100 m) and increased surface nitrate (~1 µM). Open ocean waters observed high chlorophylla(1–2 mg m−3) and microphytoplankton abundance (1.2–1.5 × 104cells l−1). Diatoms and greenNoctiluca scintillanswere the major microphytoplankton identified. ESIM observed gradual stabilization of water column with curtailment of winter signatures and strengthening ofNoctiluca scintillansblooms. Mesozooplankton biomass was higher during LWM and decreased towards ESIM with intensi...
The presence of a cyclonic eddy centred at 21°20.38'N; 66°30.68'E in the North-Eastern Ar... more The presence of a cyclonic eddy centred at 21°20.38'N; 66°30.68'E in the North-Eastern Arabian Sea (NEAS) during March 2013 is inferred from a circular patch of high chlorophyll a concentration observed in the AQUA MODIS and associated low sea level anomaly (-5cm) in the Jason II altimetry. Physical processes associated with the cyclonic eddy are investigated based on nine CTD casts and ADCP current profiles onboard FORV Sagar Sampada in a track along the diameter of the eddy. The upsloping was prominent at subsurface (12-200m) thereby shifting the D24 from 75 to 35m in the core of the eddy, resulting in shallow MLD (11m) and lowering the ambient temperature by 1°C . ADCP derived vertical current profiles shows uniform pattern up to 200m with northward currents in the eastern flank (0.6m/s) and south-south eastward currents (0.4m/s) in the western flank. Of the possible mechanisms, the observed negative wind stress curl indicates that it does not trigger divergence to facili...
The presence of a cyclonic eddy centred at 21°20.38'N; 66°30.68'E in the North-Eastern Ar... more The presence of a cyclonic eddy centred at 21°20.38'N; 66°30.68'E in the North-Eastern Arabian Sea (NEAS) during March 2013 is inferred from a circular patch of high chlorophyll a concentration observed in the AQUA MODIS and associated low sea level anomaly (-5cm) in the Jason II altimetry. Physical processes associated with the cyclonic eddy are investigated based on nine CTD casts and ADCP current profiles onboard FORV Sagar Sampada in a track along the diameter of the eddy. The upsloping was prominent at subsurface (12-200m) thereby shifting the D24 from 75 to 35m in the core of the eddy, resulting in shallow MLD (11m) and lowering the ambient temperature by 1°C . ADCP derived vertical current profiles shows uniform pattern up to 200m with northward currents in the eastern flank (0.6m/s) and south-south eastward currents (0.4m/s) in the western flank. Of the possible mechanisms, the observed negative wind stress curl indicates that it does not trigger divergence to facili...
The marine ostracod Cypridina dentata is one of the most important crustacean mesozooplankton of ... more The marine ostracod Cypridina dentata is one of the most important crustacean mesozooplankton of the North Eastern Arabian Sea ecosystem. The Cypridina dentata samples collected from North Eastern Arabian Sea, during spring inter monsoon were infested with protozoan epibionts in densities of 10 to 24 individuals per ostracod. The epibionts are suctorian ciliate protozoan species Acineta satyanandani and Paracineta karunakarani. Epibionts colonized the entire body surface, but were most numerous on the dorsal region of the carapace. The maximum number of epibionts was found on females, when compared to the male organisms. Live ostracod specimens infested with epibionts were less active than the uninfested ones and these results further suggest that epibiontic protozoans may also influence the activity of ostracods and therefore may play a substantial role in ostracod production and community dynamics. The epibiontic suctorians on ostracod Cypridina dentata were analysed and identifie...
504-506Neoceratium platycorne (Daday) F. Gomez, D. Moreira, P. Lopez-Garcia is reported for the f... more 504-506Neoceratium platycorne (Daday) F. Gomez, D. Moreira, P. Lopez-Garcia is reported for the first time from the North Eastern Arabian Sea (NEAS). Species was observed in the open ocean subsurface waters of NEAS during the late winter monsoon period. Cell density of the <i style="mso-bidi-font-style: normal">N. platycorne was 10-15 cells L-1. This record will contribute to the phytoplankton checklist of the Indian EEZ
856-859Marine epizoic diatom, Pseudohimantidium pacificum Hustedt and Krasske 1941, on copepod Co... more 856-859Marine epizoic diatom, Pseudohimantidium pacificum Hustedt and Krasske 1941, on copepod Corycaeus affinis is reported for the first time in North Eastern Arabian Sea. It was found attached exclusively to copepod C. affinis. Light Microscope and Scanning Electron Microscopic studies were made to examine the frustule morphology. With the present report from the North Eastern Arabian Sea, the biogeographic boundary of this species can be extended to the Indian waters
A monospecific bloom of thecate dinoflagellate Gonyaulax polygramma (5x 10 8 cells L -1 ) was obs... more A monospecific bloom of thecate dinoflagellate Gonyaulax polygramma (5x 10 8 cells L -1 ) was observed from the shelf waters off Mangalore (South Eastern Arabian Sea) during late summer monsoon. The bloom was observed to be subsurface (~5m depth) with chlorophyll a maxima of 13.15 μg L -1 . The species observed to be photosynthetic and no visible food vacuoles were observed within the cell. Water column stability with sufficient inorganic nutrients during the fag end of summer monsoon might have favoured the bloom species. The region observed complete exclusion of zooplankton and can suggestively due to unpalatability of the bloom species.
Crab jubilee associated with red tide of Noctiluca was observed along the central Kerala coast du... more Crab jubilee associated with red tide of Noctiluca was observed along the central Kerala coast during the summer monsoon of 2013. There was an unusual shoreward mass movement of blue swimming crab Portunus pelagicus throughout the day. Hypoxia caused by red tide of Noctiluca in the coastal waters as well as sluggish upwelling by fresh water surfacing during the intense rainfall might be the reason for this unusual coastal phenomenon.
Abstract The dynamics of Northeastern Arabian Sea (NEAS) is governed by convective mixing in wint... more Abstract The dynamics of Northeastern Arabian Sea (NEAS) is governed by convective mixing in winter and stratification during the inter-monsoon spring seasons, wherein blooms of green Noctiluca scintillans is a recurrent phenomenon. The study investigated the role of microzooplankton (MZP) in mediating the microbial food web in bloom waters of Noctiluca scintillans. The winter monsoon and inter-monsoon spring periods for the years 2009, 2011 and 2012 were considered for the present study as the occurrence and intensity of bloom fluctuates between these seasons. The MZP mediation seems to be through the top-down controls (preferential grazing) on ciliates (CTS) in bloom waters, consequently supporting high mesozooplankton standing stock and inevitably higher stock of copepods. Among the three years of observations, this relation was noticeable for the year 2012, as the intense bloom of Noctiluca (3 ×107 cells L−1) coincided with the highest number of copepods. On the contrary, in the non-bloom waters, a simple classical food web seems to be operational as diatoms dominated the phytoplankton community. Furthermore, the functional role of two CTS species viz. Codonellospsis ecaudata and Steenosemella ventricosa were most influential in structuring the community and microbial food web in the bloom events. The study suggests that during the bloom of Noctiluca scintillans, MZP mediated food web seems to be relatively significant in sustaining the high secondary production in the NEAS.
Annales de Limnologie - International Journal of Limnology, 2020
Microcystis aeruginosais a potentially toxic bloom-forming freshwater cyanobacterium, usually fou... more Microcystis aeruginosais a potentially toxic bloom-forming freshwater cyanobacterium, usually found in eutrophic water bodies worldwide. The present study reports the occurrence ofMicrocystis aeruginosaand its bloom in freshwater ponds along central Kerala (south India). Monitoring of cyanobacterial blooms was conducted from May 2019 to February 2020 along the aquatic ecosystems of central Kerala and theM. aeruginosablooms were recorded from two freshwater ponds of Kochi. Massive blooms ofM. aeruginosawas observed during the period prior to summer monsoon (May) with an abundance of 1.17 × 106cells L‑1(Station 1) and during early summer (February) latter being more thick scum (2 × 108cells L‑1) with high chlorophylla. Dense aggregates ofM. aeruginosascums were more prevalent during the periods characterised by higher Surface Water Temperature (SWT). The nutrient characteristic pattern of the study area showed the abundance ofM. aeruginosacorrelated very well with higher dissolved nit...
Journal of the Marine Biological Association of the United Kingdom, 2016
Winter cooling and persistent mixing for more than a quarter of year (November to early March) al... more Winter cooling and persistent mixing for more than a quarter of year (November to early March) along the North Eastern Arabian Sea (NEAS) results in nutrient enrichment of the euphotic column thereby triggering biological production. Hydrographic characteristics of NEAS during Late Winter Monsoon (LWM) and Early Spring Inter Monsoon (ESIM) and the influence on biological production are overviewed here. Winter convective mixing signatures were evident during LWM with low SST (24°C), high SSS (36.4), deep mixed layers (>100 m) and increased surface nitrate (~1 µM). Open ocean waters observed high chlorophylla(1–2 mg m−3) and microphytoplankton abundance (1.2–1.5 × 104cells l−1). Diatoms and greenNoctiluca scintillanswere the major microphytoplankton identified. ESIM observed gradual stabilization of water column with curtailment of winter signatures and strengthening ofNoctiluca scintillansblooms. Mesozooplankton biomass was higher during LWM and decreased towards ESIM with intensi...
The presence of a cyclonic eddy centred at 21°20.38'N; 66°30.68'E in the North-Eastern Ar... more The presence of a cyclonic eddy centred at 21°20.38'N; 66°30.68'E in the North-Eastern Arabian Sea (NEAS) during March 2013 is inferred from a circular patch of high chlorophyll a concentration observed in the AQUA MODIS and associated low sea level anomaly (-5cm) in the Jason II altimetry. Physical processes associated with the cyclonic eddy are investigated based on nine CTD casts and ADCP current profiles onboard FORV Sagar Sampada in a track along the diameter of the eddy. The upsloping was prominent at subsurface (12-200m) thereby shifting the D24 from 75 to 35m in the core of the eddy, resulting in shallow MLD (11m) and lowering the ambient temperature by 1°C . ADCP derived vertical current profiles shows uniform pattern up to 200m with northward currents in the eastern flank (0.6m/s) and south-south eastward currents (0.4m/s) in the western flank. Of the possible mechanisms, the observed negative wind stress curl indicates that it does not trigger divergence to facili...
The presence of a cyclonic eddy centred at 21°20.38'N; 66°30.68'E in the North-Eastern Ar... more The presence of a cyclonic eddy centred at 21°20.38'N; 66°30.68'E in the North-Eastern Arabian Sea (NEAS) during March 2013 is inferred from a circular patch of high chlorophyll a concentration observed in the AQUA MODIS and associated low sea level anomaly (-5cm) in the Jason II altimetry. Physical processes associated with the cyclonic eddy are investigated based on nine CTD casts and ADCP current profiles onboard FORV Sagar Sampada in a track along the diameter of the eddy. The upsloping was prominent at subsurface (12-200m) thereby shifting the D24 from 75 to 35m in the core of the eddy, resulting in shallow MLD (11m) and lowering the ambient temperature by 1°C . ADCP derived vertical current profiles shows uniform pattern up to 200m with northward currents in the eastern flank (0.6m/s) and south-south eastward currents (0.4m/s) in the western flank. Of the possible mechanisms, the observed negative wind stress curl indicates that it does not trigger divergence to facili...
The marine ostracod Cypridina dentata is one of the most important crustacean mesozooplankton of ... more The marine ostracod Cypridina dentata is one of the most important crustacean mesozooplankton of the North Eastern Arabian Sea ecosystem. The Cypridina dentata samples collected from North Eastern Arabian Sea, during spring inter monsoon were infested with protozoan epibionts in densities of 10 to 24 individuals per ostracod. The epibionts are suctorian ciliate protozoan species Acineta satyanandani and Paracineta karunakarani. Epibionts colonized the entire body surface, but were most numerous on the dorsal region of the carapace. The maximum number of epibionts was found on females, when compared to the male organisms. Live ostracod specimens infested with epibionts were less active than the uninfested ones and these results further suggest that epibiontic protozoans may also influence the activity of ostracods and therefore may play a substantial role in ostracod production and community dynamics. The epibiontic suctorians on ostracod Cypridina dentata were analysed and identifie...
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Papers by Dr. K. B. Padmakumar